Peptic ulcer (PU) is a major health problem which concerns the medical community all over the world. It is known that the major causative factor of a number of gastric pathologies including gastritis, peptic ulcers and certain gastric cancers is the Helicobacter pylori (H. pylori), a spiral microaerophilic S-shaped Gram negative bacterium which colonizes the gastric mucosa. Inflammation, injury and infection with H. pylori are the main causative factors. In spite of the substantial progress in many aspects of basic and clinical research, no clear, safe remedy is available (Newman, D. J.; Cragg. M.; Snader, K. M. (2003). Natural products as sources of new drugs over the period 1981-2002. J. Nat. Prod., 66, 1022-1037; Chimenti F., Bizzarri B., Bolasco A., Secci D., Chimenti P., Carradori S., Granese A., Rivanera D., Lilli D., Zicari A., Scaltritod M. and Sisto F. (2007). A novel class of selective anti-Helicobacter pylori agents 2-oxo-2H-chromene-3-carboxamide derivatives. Bioorganic & Medicinal Chemistry Letters, 17: 3065-3071; Newman, D. J. (2008). Natural products as leads to potential drugs: An old process or the new hope for drug discovery. J. Med. Chem.; 51:2589-2599).
Sulphonamide derivatives showed many biological activities; early and recent researchers have suggested that sulfonamides are useful for the treatment of some staphylococci infections, especially against urinary infections. It was reported that they showed the highest inhibitory effect on gram positive bacteria, i.e. Staphylococcus aureus, Nocardia asteroides, N. farcinia and Bacillus subtilis. However, sulphonamide derivatives were also reported in treatment of Chagas disease, they showed in-vitro activity against two strains of Trypanosoma cruzi. 
Furthermore, sulphonamide derivatives were used as hypoglycemic agent. Sulfonamide derivatives have several clinical applications against inflammatory bowel syndrome and other related ailments in addition to their tendency to accumulate in hypoxic tumours.
Sulfa drugs are well known inhibitors of dihydrofolate reductase. Moreover, several literatures reviews mentioned their ability to selectively inhibit the different carbonic anhydrase isoforms. Recently, some new sulfonamide derivatives with remarkable antitumor activity were prepared in laboratory (IC50 2.5-5.5 μg/mL).
The objective problem to be solved by the present invention is, therefore, to provide novel anti-ulcer and/or anti-Helicobacter pylori agents having improved effectivity and safety properties as well as low toxicity.